Using existing standards, such as the International Telecommunications Union-Telecommunications (ITU-T) G.Modem standard (i.e., the ITU-T G.707 standard), an Optical Transport Network (OTN) signal (e.g., an Optical Data Unit (ODUk) signal) may be transported and switched data transparent (i.e., all of the original bits are preserved). In other words, use of virtual concatenation and associated functions enables individual signals of which an OTN signal is composed to traverse a network using different communication paths through the network. Unfortunately, however, the associated jitter and timing cannot be guaranteed for a network-wide signal path.
As OTN signals are transported across a network using the G.modem standard, individual signals associated with the original OTN signal are switched independently and, as such, traverse different paths through the network (e.g., traversing different network elements between the originating network element the terminating network element). As a result, reassembly of the original OTN signal on the terminating node requires delay compensation to account for the different times in which the individual signals traverse the network. Unfortunately, such delay compensation is quite complicated and, therefore, expensive to implement.
As such, a system fully implemented according the G.Modem standard requires significant effort to account for delay compensation (where the effort required increases with an increase in the signal bandwidth). For example, engineering delay compensation (with respect to the required delay of ˜32 ms), Random Access Memory (RAM) interfaces, and performance requirements for OC-192/STM-64 signals (i.e., 10 G signal) is particularly difficult. Furthermore, mapping of ODU3 signals is not currently defined by the G.Modem standard since the H4 byte coding used for alignment and delay compensation only supports 256 sub-signals (and 272 sub signals are required). Therefore, the G.modem standard is limited with respect to certain applications.